The rapid growth of data traffic driven by mobile devices poses challenges on capacity of cellular networks. Multiple-input-multiple-output (MIMO) and multiuser MIMO (MU-MIMO) are technologies introduced in the 3GPP LTE and LTE-advanced standards to improve spectral efficiency. MIMO systems include an enhanced NodeB (eNB) equipped with a linear array with antenna elements placed in a horizontal line, and the eNB exploits spatial diversity in the azimuth (horizontal) domain. An increase in system capacity can be gained by deploying antennas vertically.